when I add IK, my bone moves out of place in Blender 2.8
Thanks "Serge L" here I did it.
I want to show the solution with picture so that if anyone else have this problem it help them as well.
When I created my IK bone, I deformed it and also cleared parent but mistakenly moved it away from armature, that was the problem. so as you can see from the picture below, you should extrude a new bone, deform it and clear parent then add ik, but be aware to not move it from its place.